Clutch segment

ABSTRACT

A device for coupling and decoupling two shafts or other elements of a drive train for transmitting rotations or torques especially to be used as a clutch segment in the field of motorcycle drives is provided. The clutch segment includes two parts one of which comprise troughs or recesses being arranged on a circle and offset by essentially the same angle. The troughs are at least approximately tangentially abutting an inner circle. The troughs linearly extend from their deepest point, beginning with a radius of the inner circle, at an angle towards an edge thereof and turn over towards the edge of a radius. A force application point for applying a force for coupling or decoupling the elements is located at a distance from a rotation axis of the clutch segment.

[0001] The invention discloses a device for coupling and decoupling two shafts or other elements of a drive train for transmitting rotations or torques especially to be used as a clutch segment in the field of motorcycle drives.

[0002] Coupling and decoupling shafts for transmitting rotations or torques for drives of twowheelers or motorcycles in systems that are common today is usually achieved by a clutch segment that will be shortly described below. Such a common and usual clutch segment (also listed as “inner and outer ramp” in Harley Davidson parts lists) is shown in FIG. 6.

[0003] The clutch segment consists of two segment parts (inner and outer ramp) 14, 15 that show a mainly circular shaped and flat design. Further, the two parts show troughs and pockets, respectively, or recesses 16, that have a circle-segment formed opening and are located on a circle 17, having a center M, in a manner to position the point of intersection of the secant, that marks the boundary of the circle-segments of the opening, and the symmetrical plane of the respective trough 16, on the circle 17 and that the troughs 16 are offset in relation to each other by the same angle. The center M of the circle 17 correlates to the center of rotation of the clutch segments 14, 15. The circle 17 has a radius of 14 mm.

[0004] The troughs 16 linearly open out, starting with a radius R11=5 mm at their deepest point with an angle of α_(b)=16,77° or 23,9° towards the surface of the clutch segment parts 14, 15. A common clutch segment part 14, 15 has three of the described troughs.

[0005] Part 15 of the common clutch segment has a lever 19 that is equipped with a connection point 18 for applying a force to connect or disconnect the drive elements (not shown). This connecting point is located at a range 1_(b)=40 mm from the center M of the circle 17, around which the troughs 16 are located, and thus distanced from the center M of the clutch segment element 15 as well as from the turning axis of the clutch segment and the drive elements.

[0006] Further, element 15 of the clutch segment which is equipped with the lever 19 has a flattening 20 along the circular perimeter.

[0007] The second element 14 the clutch segment has a journal like extension 21 at the perimeter.

[0008] Such clutch segments are common and well known in the state of the art and are primarily used with Harley Davidson motorcycles (named inner ramp 6 b and outer ramp 6 a).

[0009] The discussed clutch segments have a significant disadvantage in that a high amount of force is required to actuate those systems. Since the clutch lever is actuated with the left hand it is very demanding and difficult for weaker motorcyclists and especially for women to operate the clutch safely and in a correct manner.

[0010] It is thus an object of the present invention to provide a device enabling the operation of a clutch system with a significant less amount of force. It is a further object of the present invention to provide a device according to the above mentioned object that is enabled to be installed in an existing clutch/transmission housing.

[0011] Those objects are achieved by the features of the claims.

[0012] The invention is based on the gist that, by lengthening the lever for applying the force to operate the clutch segment (actuation force) and by shortening the lever for the application point of the clutch force, a change of the ratio actuation force (that is to be applied for shifting gears)/clutch force (that is required for a gear shift operation) is reached in a way that less force (actuation force) is required to effect the requisite clutch force for shifting gears.

[0013] The necessary lengthening of the length of the actuation path that is required to carry out a gear shift operation according to the above discussed change is however not practicable since, due to the limited space available in the clutch/transmission housing and due to the geometrical limitations of the clutch lever and the anatomical limitations of an average built operator, respectively, a lengthening of the actuation path/travel is not possible.

[0014] Therefore the present invention is further based on the gist that the required actuation travel for operating the clutch can be reached by a change of geometry of the troughs/recesses, by a variable course of the clutch force that has to be overcome, and by the fact that an additional tuning of the geometry of the troughs as well as the levers enables an optimizing of the force required to operate the clutch.

[0015] In the following, the invention will be described with reference to a preferred embodiment and to the drawings, in which:

[0016]FIG. 1 is a top view of a clutch segment according to the present invention, wherein

[0017]FIG. 1a is a fixed or static segment part, and FIG. 1b is a flexible or movable segment part with a lever for applying the force for coupling or decoupling the elements of a drive train;

[0018]FIG. 2 shows details of a clutch segment according to the present invention, wherein

[0019]FIG. 2a is a cross-sectional view of a trough/recess according to the present invention, and

[0020]FIG. 2b is a further detail of a trough/recess according to the present invention;

[0021]FIG. 3 is a preferred embodiment of a clutch segment according to the present invention, wherein

[0022]FIG. 3a is a side view of a clutch segment with a lever for applying the force for coupling and decoupling the elements of a drive train,

[0023]FIG. 3b is a top view of the element shown in FIG. 3a, and FIG. 3c is a clutch segment part according to FIGS. 3a and 3 b for static/fixed installation in the clutch/transmission housing;

[0024]FIG. 4 is a further preferred embodiment of a clutch segment according to the present invention, wherein

[0025]FIG. 4a is a side view of a clutch segment having a lever for applying the force for coupling and decoupling the elements of a drive train,

[0026]FIG. 4b is a top view of the element shown in FIG. 4a, and

[0027]FIG. 4c is a clutch segment part according to FIGS. 4a and 4 b for static/fixed installation in the clutch/transmission housing;

[0028]FIG. 5 is a further preferred embodiment of a clutch segment according to the present invention, wherein

[0029]FIG. 5a is a side view of a clutch segment having a lever for applying the force for coupling and decoupling the elements of a drive train,

[0030]FIG. 5b is a top view of the element shown FIG. 5a, and

[0031]FIG. 5c is a clutch segment part according to FIGS. 5a and 5 b for static/fixed installation in the clutch/transmission housing; and

[0032]FIG. 6 is a known common clutch segment, wherein

[0033]FIG. 6a is a clutch segment for static/fixed installation in the clutch/transmission housing, and

[0034]FIG. 6b is a known common clutch segment with a lever for applying the force for coupling and decoupling the elements of a drive train.

[0035]FIG. 1 shows two corresponding clutch segment parts 1, 6 according to the present invention. FIG. 1a shows a clutch segment part 1 comprising three troughs/recesses 2 which are positioned on a circle, offset in relation to each other by the same angle, such that the troughs 2 tangentially abut or at least approximately tangentially abut an inner circle and are rotationally symmetrical aligned around the center M of the inner circle 3. The troughs 2 have a circle-segment shaped opening at the upper surface of the clutch segment 1, the straight side or secant of the circular segments touching the inner circle 3 with their mid-point, at least approximately tangentially. Clutch segment 1 further comprises a connecting device 4 a. The connecting device 4 a is preferably designed as an opening or passage which is preferably circular shaped and concentric with the inner circle 3. The connecting device 4 a comprises additional elements to connect parts of the drive train, mainly gear elements, in a preferred embodiment. In a preferred embodiment the radius of the inner circle 3 and the radius of the opening of the device 4 are more or less identical. The radius R3 of the inner circle 3 is, according to the present invention, about 6 mm to 8 mm, preferably about 6,7 mm.

[0036] The clutch segment part 1 is preferably substantially circular shaped and comprises a land or a journal like extension 5. Extension 5 is preferably used for a static/fixed installation of clutch segment 1 in the clutch/transmission housing (not shown).

[0037]FIG. 1b shows a clutch segment part 6 according to the present invention, that comprises troughs 2, an inner circle 3 and a connecting device 4 b, the troughs 2 and the inner circle 3 corresponding to those described with regard to the clutch segment part 1 of FIG. 1a.

[0038] Further, clutch segment part 6 comprises an extension or lever 7 for applying the force for coupling and decoupling the elements of a drive train wherein the lever comprises element 8 for taking up the applied force. In a preferred embodiment this element 8 or the lever 7 are designed as a hook. The distance L₁ between the application point of the force 9 on the element 8 and the lever 7, respectively, and the center of the inner circle 3 and the connecting feature 4 b, respectively, is in the range from about 42 mm to 46 mm, and is preferably about 44 mm.

[0039] Furthermore, the clutch segment part 6 has a preferably circular shaped design with a flattening 10.

[0040]FIG. 2 shows a detail of troughs 2 according to the present invention. FIG. 2a shows a sectional view of a preferred trough 2. The trough 2 has a radius R11 of 5 mm at its deepest point 11 which turns over to a surface 12 inclined at an angle α₁ that extends to the upper edge of the trough 2. The straight linear side wall 12 turns over towards the edge of the trough 2 to a progressively increasing radius R12, as shown in FIG. 2b.

[0041] The angle α₁ is, according to the present invention, in the range of about 26° to 33°, in a preferred embodiment about 28° and 31°. The radius R12 is in the range of about 38° to 42°, and preferably about 40°.

[0042] As a comparison, FIG. 2a shows an angle α_(b) at which the side wall 12 of the trough 2 extends to the edge of the trough 2 in the state of the art. The angle α_(b) has a value of 16,77° and 17°, respectively, and, in a further common embodiment, 23,90°.

[0043]FIGS. 3, 4 and 5 show special embodiments of the clutch segment according to the present invention, wherein the measurements and the geometry of the troughs 2, inner circles 3, connecting devices 4 a, 4 b and force application points 9 corresponds to embodiments discussed with regard to in FIGS. 1a and 1 b.

[0044]FIG. 3 shows a preferred embodiment according to the present invention in which the clutch segment part 6 (FIGS. 3a and 3 b) has a substantially rectangular shape in a side view. FIG. 3c shows a clutch segment part 1 according to the one discussed and shown in FIG. 1a.

[0045]FIG. 4 shows a preferred embodiment of a clutch segment according to the present invention, wherein the lever 7 of the clutch segment part shown in FIGS. 4a and 4 b is bent and (at right angles) and wherein the connecting device 4 b is extended in the opposite direction of the bending direction of the lever 7. The clutch segment part 1 shown in FIG. 4c further has a triangle shaped design with attachment means 13 located at the edges. The attachment means 13 can be designed as, e.g., a hole, groove or pin.

[0046]FIG. 5 shows clutch segment parts 1 (FIGS. 5c) and 6 (FIGS. 5a and 5 b) according to the present invention, the clutch segment 6 shown in FIGS. 5a and 5 b corresponding to the clutch segment 6 shown in FIGS. 4a and 4 b and the clutch segment 1 shown in FIG. 5c corresponding to the clutch segment 1 shown in FIG. 3c.

[0047]FIG. 6 shows a common design of the clutch segment part 6 (FIG. 6b) and the clutch segment part 1 (FIG. 6a) as already mentioned in the discussion of the state of the art. The known clutch segments 14 and 15 according to the state of the art show troughs 16 which have a geometrical design already discussed with regard to FIG. 2, that means α_(b)=17°. The troughs 16 are located around a circle 17 having a radius R17 of 14 mm in a manner similar to the troughs 2 according to the present invention. The force application point 18 of the lever 19 of the clutch segment 15 is dislocated at a range Lb of the center of the circle 17, wherein the length L_(b) has a value of 40 mm.

[0048] The clutch segment according to the present invention is especially suited for the use in motorcycle clutches and particularly for Harley Davidson motorcycles.

[0049] The embodiment of the clutch segment parts 1 and 6 as shown in FIG. 3 are especially suited for use in the Harley Davidson models EVO and Big Twin (abbrev. FXR, FXD, FXST, FLST, FLH) starting from production year 1987, depending on the individual design of the clutch segment. The preferred embodiments of the clutch segment parts 1 and 6 as shown in FIG. 4 are especially suited for the use in XLH models year 1984 to 1992 and up. The preferred embodiments of the clutch segment parts 1 and 6 as shown in FIG. 5 are especially suited for use in XLH models year 1993 and up. Further, the clutch segments according to the present invention are suited for use in all Harley Davidson Sportster models year 1984 and up.

[0050] Due to the special arrangement of the troughs 2 and the force application point 9 of the clutch segment and the special geometrical design of the recesses 2, a significant reduction of the required force for actuating the clutch is achieved without the necessity of prolonging the travel/path of the clutch lever or an enlargement of the clutch/transmission housing. This leads to an increased comfort level for driving and to a significant increase in safety by a relaxed driving, requiring less effort. 

What is claimed is:
 1. A device for coupling and decoupling two shafts or other elements of a drive train for application of rotations or torques, in particular for the use as a clutch segment in the field of motorcycle drives, the clutch segment part comprising troughs or recesses being arranged on a circle and offset by essentially the same angle, the troughs at least approximately tangentially abutting an inner circle, characterized in that the inner circle has a radius R3 of about 6 mm to 8 mm, and that the troughs linearly extend from their deepest point, beginning with a radius (R11) of about 5 mm, at an angle (α₁) of about 26° to 33° towards an edge thereof and turning over towards the edge to a radius (R12) of about 36 mm to 42 mm; and in that a force application point for applying a force for coupling or decoupling the elements is located at a distance L₁ of about 42 mm to 46 mm from a rotation axis (M) of the clutch segment.
 2. The device according to claim 1, wherein the inner circle has a preferred radius (R3) of about 6,7 mm.
 3. The device according to claim 1, wherein the troughs linearly extend towards the edge at an angle (α₁) of 28° or 31°.
 4. The device according to claim 1, wherein the troughs turn over towards the edge with a radius (R12) of preferably about 40 mm.
 5. The device according to claim 1, wherein the radius (R12) progressively increases towards the edge of the troughs up to a value of about 40 mm.
 6. The device according to claim 1, wherein the application point for applying the force for coupling and decoupling the elements is located at a range L₁ of about 44 mm away from the center of rotation (M) of the clutch segment part.
 7. The device according to claim 1, wherein the troughs have a circle-segment shaped opening and are flat towards the surface of the clutch segment.
 8. The device according to claim 1, wherein the troughs are rotationally symmetrical arranged around the center of rotation (M) of the inner circle.
 9. The device according to claim 1, wherein the center (M) of the inner circle and the axis of rotation (M) of the clutch segment lie on one another.
 10. The device according to claim 1, wherein the clutch segment comprises three troughs.
 11. The device according to claim 1, wherein the clutch segment comprises a connecting device to receive at least one of the shafts or at least one element of a drive train.
 12. The device according to claim 1, wherein the coupling device, for receiving at least one shaft or at least one element of a drive train and the inner circle and the axis of rotation (M), respectively, of the clutch segment are arranged concentrically.
 13. The device according to claim 1, wherein the clutch segment is substantially circular shaped.
 14. The device according to claim 1, wherein the clutch segment is designed as a segment of a circle.
 15. The device according to claim 1, wherein the clutch segment comprises an extension and a lever, respectively, for applying a force for coupling or decoupling the elements.
 16. The device according to claim 15, wherein the extension and the lever, respectively, is hook shaped or has a hook shaped section.
 17. The device according to claim 1, wherein the extension and the lever, respectively, is bent at right angles.
 18. The device according to claim 1, wherein the clutch segment has a substantially triangular shape.
 19. The device according to claim 1, to be used as a clutch segment in motorcycles.
 20. A Clutch segment part comprising troughs, which have the same geometrical measurements and which are arranged as those of a corresponding clutch segment part according to claim 1, wherein the clutch segment part comprises elements for static installation in a clutch/transmission housing.
 21. A device for coupling and decoupling two shafts or other elements of a drive train to apply rotations and torques especially to be used as clutch segment in the field of motorcycle drives, comprising a clutch segment part according to claim 1 and a clutch segment part according to claim 20 wherein balls are positioned between the devices and, of which two portions are received by two corresponding troughs of the devices. 